174 Rydberg : Studies on Rocky Mountain Flora 



Plant about 4-6 dm. high, simple. 



Leaves serrate or snbentire ; basal leaves I cm. or more, slender- 



petioled. 9. 6". longipetiolatus. 



Stem leaves with long, triangular lobes ; basal leaves 5 cm. or less. 



10. S. fiilgens. 

 Basal leaves cuneate, spatulate or broadly oblanceolate, subentire at the base. 

 Lower stem leaves spatulate with a broad-winged petiole ; upper ones 



sessile and with much enlarged bases. il. S. c7-ocatits. 



Stem leaves neither broad- winged nor with much enlarged bases. 



Basal leaves crenate above the middle. 12. S. cyinbalarioidcs. 



Basal leaves angularly dentate. 13. 5". Jcviesii. 



Basal leaves sharply dentate or serrate above the middle. 

 Lower stem leaves cuneate, plant 3-4 dm. high. 



14. S. stibcuneatus. 

 Lower stem leaves oblanceolate ; plant about 2 dm. high. 



15. S. acutidens. 

 Leaves thin. 



Basal leaves ovate or more commonly cordate, serrate. 16. ^. pseudaiircus. 

 Basal leaves obovate or oval, crenate or sinuate-dentate. 

 Stem leaves ovate in outline, with broad segments. 



17. 6'. platylobus. 

 Stem leaves lanceolate or oblanceolate in outline, with narrow segments. 



18. S. flavovirens. 

 Stem leaves spatulate or oblanceolate in outline, with short and broad 



segments. 19. 6*. aurellus. 



Head discoid. 



First basal leaves reniform. 20. S. ncphrophylhis. 



None of the leaves reniform. 



Plant stout ; stem leaves with broad laciniate segments. 



21. 5'. Idahoensis. 

 Plant slender ; stem leaves with narrow segments. 



Plant yellowish or light green ; bracts not purple-tinged. 



17. S. flavovirens. 

 Plant dark green. 



Basal leaves crenate ; head S-lo mm. high ; bracts purple-tinged, 



linear. 22. .S". paitciflorus. 



Basal leaves wavy ; heads about 6 mm. high ; bracts broadly lanceo- 

 late or oblong, not purple-tinged. 23. S. fcdifoUiis. 



6. Senecio compactus (A. Gray) Rydb. Mem. Torr. Club, 5 : 



342. 1893 

 Senecio aureus var. compactus A. Gray, Syn. Fl. i" : 391. 1884. 

 Dr. Gray's description covers two if not three species. For 

 which of these ^. conipatus should be used is a matter of ques- 

 tion. I have adopted it for the plant of the plains with a dense 

 cyme and usually pinnatifid-dentate stem leaves. Dr. Gray evi- 

 dently had this plant in mind when he adopted the name com- 



